Epidemiological data indicate that patients who experience a traumatic brain injury (TBI) have an elevated risk of developing a substance use disorder (SUD), but the underlying neurobiological connections remain unclear. To further understand the relationship between TBI and SUD, we investigated the effects of TBI on the abuse-related effects of oxycodone in preclinical models. Our evaluation utilized a lateral fluid percussion injury of moderate severity in adult male Sprague-Dawley rats. In the first aim, we tested the hypothesis that moderate TBI increases the risk for relapse to an opioid use disorder as measured by reinstatement of lever-pressing behavior following extinction in an intravenous oxycodone self-administration procedure. In the second aim, we tested the hypothesis that moderate TBI increases physiological dependence to oxycodone as measured by decreases in food-reinforced lever-pressing behavior and increases in other withdrawal behaviors in both precipitated withdrawal and spontaneous withdrawal. In tests for self-administration, brain-injured subjects, relative to non-injured subjects, showed no significant differences in the number of oxycodone-reinforced sessions required to meet stable maintenance criteria for lever-pressing behavior. Likewise, brain-injured subjects showed no significant differences in the number of non-reinforced sessions to meet extinction criteria for lever-pressing behavior relative to non-injured subjects. In tests for reinstatement, non-injured subjects reinstated responding under oxycodone-associated cue- and oxycodone prime-induced conditions, however, brain-injured subjects did not reinstate lever-pressing behavior under any conditions. In tests for physical dependence, brain-injured subjects showed no significant differences from non-injured subjects with regards to their mean withdrawal scores or food-reinforced lever-pressing behavior. Overall, these data suggest that brain-injured patients no significant pre-morbid history of opioid abuse are at a lesser risk of relapse to opioid use disorders. Moreover, the characteristic withdrawal syndrome in opioid-dependent patients may not contribute to continued opioid abuse to a greater degree in brain-injured patients than compared to non-injured patients.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.

Nicotine replacement therapy (NRT) is a pharmacotherapy used commonly to help tobacco smokers quit smoking. All forms of NRT are demonstrably efficacious for this indication, and several forms, including transdermal nicotine (TN) are available over-the-counter in the United States. NRT is less efficacious in women than in men, although the specific reasons for this gender difference are unknown. NRT generally, and TN specifically, is thought to work, at least in part, by suppressing withdrawal symptoms in abstinent smokers. While TN-induced withdrawal suppression has been demonstrated, the degree to which this withdrawal suppression is influenced by smokers' gender is uncertain. The purpose of this acute laboratory study is to determine if TN-induced withdrawal suppression is influenced by smokers' gender.One hundred twenty eight overnight-abstinent smokers completed four, double-blind, randomized, 6.5-hour laboratory sessions in which further cigarette abstinence was required. Sessions differed by TN dose (0, 7, 21, or 42 mg). All sessions were double-blind and randomly ordered. Each session included regular assessment of subjective symptoms of nicotine/tobacco withdrawal, subjective effects of transdermal nicotine dose, psychomotor performance, heart rate and plasma nicotine level. Results from this laboratory study revealed clear nicotine dose-related effects for plasma nicotine and heart rate, symptoms of nicotine intoxication (e.g. Nausea, Lightheaded) and suppression of Urges to smoke and Craving. Many DSM IV nicotine/tobacco withdrawal symptoms did not show dose-related suppression (e.g. Irritability/frustration/anger, Anxious, Difficulty concentrating). Importantly, results from this study indicated that there were very few differences between men and women in nicotine-induced suppression of the nicotine/tobacco withdrawal syndrome. Future research addressing this important issue may benefit from focusing on a potential interaction between gender and other effects of TN (i.e., blunting the effects of a concurrently administered cigarette) and/or on other triggers for relapse (i.e., smoking-related stimuli).

A dissertação examina o regime jurídico do direito de retirada de sócios de sociedade simples e de sociedade limitada a partir da vigência do CC/2002. Para tanto, parte do estudo de sua natureza jurídica e de uma releitura dos fundamentos jurídicos deste instituto. Serve-se, ainda, de considerações sobre a evolução histórica do direito de retirada tanto no direito nacional quanto em ordenamentos estrangeiros (Alemanha, Espanha, França, Itália e Portugal). Assume especial relevo neste percurso o tratamento dado ao direito de retirada de sócio de sociedade limitada e a construção pela doutrina e pela jurisprudência do instituto da dissolução parcial stricto sensu sob a vigência do Decreto n° 3.708/1919 e do Código Comercial de 1850, respectivamente. Com base nos pressupostos acima, a dissertação passa a abordar de forma pormenorizada o direito de retirada de sócios de sociedade simples e sociedade limitada previsto no CC/2002, identificando as hipóteses em que é legalmente autorizada e aprofundando-se no exame do seu regime jurídico em cada tipo societário. Por fim, analisando as hipóteses de dissolução total de sociedades previstas pelo CC/2002, procura definir se e em quais hipóteses o instituto da dissolução parcial stricto sensu ainda é aplicável. / This dissertation examines the legal framework of the right of partners to withdraw from a simple company (sociedade simples) and from a limited liability company (sociedade limitada) under the current Brazilian Civil Code (CC/2002). For such purposes, the dissertation starts by studying its legal nature and revisits its legal basis. It also considers the historical development of the right to withdraw under Brazilian law and that of certain other jurisdictions (Germany, Spain, France, Italy and Portugal). In the context of this historical analysis, it assumes special importance the right of partners to withdraw from a limited liability company (sociedade limitada) and the doctrinal and case law creation of the institute of partial dissolution (dissolução parcial stricto sensu) under Decree No 3,708/1919 and the Commercial Code of 1850, respectively. Having regard such review, the dissertation addresses, in detail, the right of partners to withdraw from a simple company (sociedade simples) and a limited liability company (sociedade limitada), as contemplated by the current Brazilian Civil Code (CC/2002), thereby also identifying when the same is authorized in each type of corporate vehicle and each applicable legal framework. Finally, by analyzing the scenarios for dissolution of companies contemplated by the current Brazilian Civil Code (CC/2002), it seeks to identify whether and in which scenarios the partial dissolution (dissolução parcial stricto sensu) is still applicable.

This study examined how student characteristics could be used to predict whether or not a community college student would persist in an online course. The research question guiding the study was, “Which student characteristics can be used to best predict the persistence of community college students in online courses?” The student characteristics examined were learning style, locus of control, computer experience and access, previous online experience and demographics. A survey instrument consisting of two previously developed instruments and a Computer Experience scale that was created by the researcher specifically for this study, was administered to online students at one Florida community college for the pilot study and five additional Florida community colleges for the full study. Confirmatory and exploratory factor analysis were conducted on the computer experience scale to determine if there was an underlying hidden structure. Stepwise logistic regression was completed to determine the student characteristics that were significant predictors of online persistence, as well as an equation that could be used to predict whether or not a community college student would persist in an online course. Confirmatory and exploratory factor analysis revealed that the Computer Experience scale consisted of three underlying subscales. The researcher named the three subscales based on the similarities of the variables that were associated with each factor: Factor one (basic computer skills); Factor two (Internet/email skills); Factor three (interactive computing skills). Three of the initial 25 predictor variables were found to be significant predictors of community college online persistence: GPA, auditory learning style, basic computer skills. An increase in both auditory learning style and basic computer skills was associated with a decrease in the odds of course persistence. On the other hand, an increase in GPA was associated with an increase in the odds of course persistence. Additionally, an equation to predict whether or not an online community college student would persist in an online course was developed. Implications for community college administrators as well as recommendations for future studies are also provided in the study. / Dissertation / PhD

A dissertação examina o regime jurídico do direito de retirada de sócios de sociedade simples e de sociedade limitada a partir da vigência do CC/2002. Para tanto, parte do estudo de sua natureza jurídica e de uma releitura dos fundamentos jurídicos deste instituto. Serve-se, ainda, de considerações sobre a evolução histórica do direito de retirada tanto no direito nacional quanto em ordenamentos estrangeiros (Alemanha, Espanha, França, Itália e Portugal). Assume especial relevo neste percurso o tratamento dado ao direito de retirada de sócio de sociedade limitada e a construção pela doutrina e pela jurisprudência do instituto da dissolução parcial stricto sensu sob a vigência do Decreto n° 3.708/1919 e do Código Comercial de 1850, respectivamente. Com base nos pressupostos acima, a dissertação passa a abordar de forma pormenorizada o direito de retirada de sócios de sociedade simples e sociedade limitada previsto no CC/2002, identificando as hipóteses em que é legalmente autorizada e aprofundando-se no exame do seu regime jurídico em cada tipo societário. Por fim, analisando as hipóteses de dissolução total de sociedades previstas pelo CC/2002, procura definir se e em quais hipóteses o instituto da dissolução parcial stricto sensu ainda é aplicável. / This dissertation examines the legal framework of the right of partners to withdraw from a simple company (sociedade simples) and from a limited liability company (sociedade limitada) under the current Brazilian Civil Code (CC/2002). For such purposes, the dissertation starts by studying its legal nature and revisits its legal basis. It also considers the historical development of the right to withdraw under Brazilian law and that of certain other jurisdictions (Germany, Spain, France, Italy and Portugal). In the context of this historical analysis, it assumes special importance the right of partners to withdraw from a limited liability company (sociedade limitada) and the doctrinal and case law creation of the institute of partial dissolution (dissolução parcial stricto sensu) under Decree No 3,708/1919 and the Commercial Code of 1850, respectively. Having regard such review, the dissertation addresses, in detail, the right of partners to withdraw from a simple company (sociedade simples) and a limited liability company (sociedade limitada), as contemplated by the current Brazilian Civil Code (CC/2002), thereby also identifying when the same is authorized in each type of corporate vehicle and each applicable legal framework. Finally, by analyzing the scenarios for dissolution of companies contemplated by the current Brazilian Civil Code (CC/2002), it seeks to identify whether and in which scenarios the partial dissolution (dissolução parcial stricto sensu) is still applicable.

No description available.

The aim of the research is to assess the sustainability of groundwater supply and the suitability of hand-drilling techniques for accessing groundwater for irrigation practices along the shallow alluvial floodplains of River Benue, NE Nigeria. Hand-drilling techniques are affordable means for the farmers to abstract water from these shallow aquifers. Determining the most sustainable hand-drilling techniques (taking into account the hydrology and sedimentology of the floodplain) will improve farming activities and food security in this region and the country at large. Hydrological data (obtained from fieldwork and modelling) demonstrate that the River Benue is the main source for recharge of the shallow alluvial aquifers of the floodplain during the dry season period. Water table heights were estimated by resistivity survey using ABEM Terrameter equipment and measured by automatic piezometer instruments. Floodplain sedimentology and hydrogeology were assessed at seventeen natural riverbank outcrops and twelve hand-drilled boreholes. At each location, sediment samples were collected from every exposed sedimentological unit. Locations and elevations were measured using a ProMark3 dual frequency GPS instrument, to create a detailed topographic map with updated contours. Twenty-four electrical resistivity sounding profiles and twelve-groundwater measurement were also obtained to explore the groundwater level of the floodplain. The resistivity results confirm the availability of water in the alluvial aquifers of the floodplain. In order to determine the most appropriate hand drilling techniques, a Field Shear Vane Tester was used to measure sediment shear strength at twelve different borehole locations. Shear strength forces were higher on clayey silt and sandy silt, and lower on sand formations. It appeared that in some areas of the floodplain, the farmers are already above the shear strengths that can be provided by human power. Hence, any increase of the hardness of the surface of the sediment would make low-cost hand drilling impractical. Particle size analysis for the sediment samples showed that the samples were largely sandy in nature, which enables easy movement of water through the layers for aquifer recharge. Magnetic susceptibility (used to classify the source of sediment and the process of their formation) revealed that the main source of the sedimentary materials was upstream of the study site and varies little over time. The groundwater level of the study area decreased away from River Benue valley during the dry season period. One perched aquifer formations and possibly two others were observed in three different locations, which reflects a low-permeability stratigraphic unit (such as lens of clayey silt) within alluvial sands. These should be avoided by farmers, as they are likely to provide water only in the short-term. Finally, groundwater modelling was undertaken (with various scenarios) for the River Benue floodplain using acquired sedimentology and hydrology data integrated into MODFLOW software. The results revealed that low-cost hand-drilling techniques such as augering and jetting remain possible for abstracting the shallow alluvial aquifers on the floodplain for irrigation farming in the study area, unless the most likely low river water stages in River Benue, over-exploitation of the shallow alluvial floodplain groundwater and drought scenarios occur.

This qualitative research project focused on the interviews of 27 low socio-economic students at a research university in the southwestern United States. The students had already withdrawn from the university or were in the process of withdrawing. The study seeks to provide increased understanding of how students negotiate the decision-making process to withdraw from the first university they attended after high school. The theoretical lenses of student departure theories (Astin, 1993; Bean, 1983; Tierney, 1992; and Tinto, 1993) and decision-making theories (Becker, 1976; Frank, 1987; Kahneman, 2003; March, 1994; Scott, 2000) were combined. The Decision-Making Process Model of Student Departure is offered as a new theoretical framework that combines decision-making theories and student retention theories. This conceptualization is unlike other student departure models because it includes the proposition that forces push at the student from within the institution and forces pull them from outside the institution. In addition, it is different from other student departure models because it includes the discussion about how students think about their process to withdraw - it is not meant to describe their behaviors. Financial, academic and psychological stresses (from both within and outside the institution) influenced how the students negotiated the decision-making process to leave the institution. The students did not seek out institutional agents (advisors or faculty members) for advice when they were struggling academically. They developed their own strategies or went to their family members for advice, many of whom had never been to college.

Today, more Americans die each year because of drug overdoses than are killed in motor vehicle accidents. In fact, in 2015, more than 33,000 individuals died due to an overdose of heroin or prescription opioids. Sadly, 40-60 % of patients on current opioid addiction treatment medications relapse. Studies have shown that the addiction/abuse liability of opioids are abolished in mu opioid receptor (MOR) knock-out mice; this indicates that the addiction and abuse liability of opioids are mainly mediated through MOR. Utilizing the “message-address concept”, the our laboratory reported a novel non-peptide, reversible MOR selective ligand 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6α (isoquinoline-3-carboxamido)morphinan (NAQ). Molecular modeling and mutagenesis studies revealed that the selectivity of NAQ for MOR is because of the π-π stacking of the isoquinoline ring of NAQ with W318. Therefore, other heterocyclic ring systems were explored to obtain a diverse library of compounds with similar or different molecular interactions and pharmacologic characteristics as NAQ. The newly designed compounds were indole analogs of 6α/β-naltrexamine. The compounds were synthesized and the affinity and selectivity for MOR determined using the radioligand binding assay while the functional activity at MOR was determined using the [35S]GTPγS binding assay. The indole analog of 6α-naltrexamine substituted at position 7 (compound 6) was found to be very potent and had the lowest efficacy in the [35S]GTPγS functional assay while the indole analog of 6β-naltrexamine substituted at position 2 (compound 10) was identified as a MOR agonist and had the greatest efficacy. In vivo studies were conducted using the warm-water immersion assay to find whether the synthesized compounds had antinociceptive effects and/or blocked the antinociceptive effects of morphine. Not surprisingly, compound 10 was identified as an opioid agonist while compound 6 almost completely blocked morphine’s antinociceptive effects. The opioid antagonist effect of compound 6 was found to be dose dependent with an AD50 of 2.39 mg/kg (0.46-12.47). An opioid withdrawal assay was conducted on compound 6 using morphine-pelleted mice. Compound 6 produced significantly less withdrawal symptoms at 50 mg/kg than naltrexone at 1 mg/kg. Therefore, compound 6 has the potential to be used in opioid addiction and withdrawal treatment.